Lubricant for extrusion of thermoplastics

ABSTRACT

An external lubricant useful in the extrusion of thermoplastic goods which consists essentially of water, a water-soluble polyol of the formula R(OH)n wherein R is a multivalent hydrocarbyl radical having two to five carbon atoms and a valence equal to n, and n is the integer 2 or 3, and at least one detergent selected from the group consisting of (a) a nonionic detergent of the formula   WHEREIN R&#39;&#39; is an alkyl hydrocarbon radical having eight to 20 carbon atoms and m has a value in the range of six to 20 and (b) an anionic detergent of the formula   WHEREIN R&#39;&#39;&#39;&#39; is an alkyl hydrocarbon radical having eight to 20 carbon atoms and M is selected from the group consisting of sodium, potassium and ammonium.

United States Patent 1 Mixon et al. Aug 28, 1973 LUBRICANT FOR EXTRUSIONOF Primary Examiner-Patrick P. Garvin THERMOPLASTICS AssistantExaminer-Andrew H. Metz [75] lnventors: Donald E. Mixon, Bartlesville,Okla; Attorney-Young and Oulgg Estil N. Barnes, lnkster, MlCh. [57]ABSTRACT [73] Ass'gnee: g g i Company An external lubricant useful inthe extrusion of thermoart 0 plastic goods which consists essentially ofwater, a wa [22] Filed: Dec. 3, 1971 ter-soluble polyol of the formulaR(Ol-l),, wherein R is I a multivalent hydrocarbyl radical having two tofive [2]] Appl' 204709 carbon atoms and a valence equal to n, and n isthe integer 2 or 3, and at least one detergent selected from [52] U.S.Cl 252/33.4, 252/49.3, 252/49.5, the group consisting of (a) a nonionicdetergent of the 252/52 R formula [51] Int. Cl C10m 3/34 [58] Field ofSearch 252/33.4, 49.3, 49,5, '--0 [CHzCH1- ]m'- I wherein R is an alkylhydrocarbon radical having eight [56] References C'ted to 20 carbonatoms and m has a value in the range of UNITED STATES PATENTS SIX to 20and (b) an anionic detergent of the formula 3,000,826 9/l96l Gilland252/49.3 3,024,198 3/1962 Harrington et al. 2s2/49.s x HQ 3,264,2428/1966 Teot 252/52 R X I 3,304,258 2/l967 White et al. 252/49.3 X3,387,073 6/1968 Larsen 264/209 x wherein R 15 an alkyl hydrocarbonradical having 3,425,940 2/1969 Norton 252/33.4.x ight'to 20 carbonatoms and M is selected from the 3,495,962 2/1970 Norton et al. 252/29 Xgroup consisting of sodium, potassium and ammonium. 3,649,538 3/l972Hotten 252/49.5 X

4 Claims, No Drawings LUBRICANT FOR EXTRUSION F THERMOPLASTICS Thisinvention relates to a new and improved fluid for lubricatingthermoplastic extrusions.

It is known to pass hot thermoplastic extrudate such as a pipe into awater bath for the purpose of cooling the extrudate and fixing it in thedesired shape. It is also known that hot thermoplastic pipe can be fixedin a uniformly round shape by passing it through a sleeve of fixeddiameter which sleeve leads directly into the water bath. Thus the hotpipe is rounded to the desired diameter and immediately thereafter fixedupon entering the water bath. The hot thermoplastic, however, tends tostick to the walls of the sleeve as the thermoplastic passes through thesleeve. This causes various imperfections in the surface of theextrudate such as streaks, pits, and holes. In addition, the material ofthe sleeve tends to corrode due to contact with the hot extrudate.

There is thus presented a requirement for an agent which will lubricatethe passage of hot extrudate through a sleeve opening into a water bath.The agent must not be a contaminant for the bath; it must protect thesurface of the extrudate from damage by the sleeve; and it must detercorrosion of the sleeve material.

Thus, in accordance with this-invention, there is provided an externallyapplied lubricant which is highly useful in the extrusion of hotthermoplastic materials. In one extrusion procedure, for example, athermoplastic material is extruded by any known method to, form a pipe;the pipe, which is hot, is thereafter introduced into a water quenchbath by way of a sleeve opening, herein referred to as a sizing ring,having a diameter only just large enough to permit passage of the pipeinto the water bath. The sizing ring can be used to reduce the diameterof the extrudate and to thus produce a uniformly round pipe. Since thelevel of water in the bath is above the sizing ring opening, the pipefits tightly enough in the sizing ring to form a seal. The lubricant ofthis invention is therefore poured on the outside external pipe surfacewhich contacts the sizing ring immediately before it passes through thesizing ring to lubricate its passage through the ring. Sufficientlubricant is utilized to effect smooth flow and complete coverage of theextrudate surface. Excess lubricant which drips from the pipe surfacecan be recovered and reused to lubricate as above described. Anylubricant of this invention which enters the water bath causes nodeleterious result to the bath, that is, the lubricant isnoncontaminating and there is no foaming. In addition, the lubricant ofthis invention preserves the surface of the pipe and it is not marred orstreaked in any way upon passage through the ring and, further, thetendency of the sizing ring which is metal, usually brass or aluminum,tocorrode in the presence of the hot thermoplastic is reducedconsiderably if not completely eliminated by use of the lubricant ofthis invention.

The lubricant of this invention is, broadly, a waterpolyol-detergentmixture wherein the quantity ofdetergent in the mixture is no greaterthan 6 percent by volume of the volume of the water-polyol combination.More specifically, the polyol and water are combined such that the ratioof polyol added to the water to form the polyol-water combination is inthe range of 0.25 to 1.5, and preferably 0.75 to 1.25, parts by volumepolyol per one part by volume of water. In one preferred embodiment, theratio of polyol added to water is one part by volume polyol to one partby volume water. To complete the lubricant of this invention thedetergent is added to the polyol-water combination such that thequantity of detergent added is in the ratio range of 0.5 to 6,preferably 1 to 4, and still more preferably 2 to 3, parts by volumedetergent per parts by volume of the polyol-water combination. In onepreferred embodiment the lubricant of this invention is prepared bycombining 1 quart of water, 1 quart of polyol, and 50 millileters ofdetergent. This is approximately 2.7 parts by volume detergent per 100parts by volume of the polyol-water combination. Since volume istemperature dependent, it is desirable that the volumes of theconstituents be measured at approximately the same temperature whereinthe temperature of measurement is less than the boiling point of thelowest boiling point constituent employed.

The water used herein can be from any conventional source of industrial,residential, or commercial potable water. It is desirable that the waternot be brackish or otherwise highly salty. Y

wherein R is a multivalent hydrocarbyl radical having 2 to 5 carbonatoms and a valence equal to n, and n is an integer having the value 2or 3.

Examples of polyols useful herein include glycerol, ethylene glycol,l,2-propane diol, l,3-butane diol, 2,3 butane diol, 2,3-pentane diol,1,3,5-pentane triol, and l,2, 4-butane triol, wherein glycerol, ethyleneglycol, and l,2-propane diol are preferred, with glycerol being the mostpreferred.

The detergent useful herein is selected generally from water-solublenonionic and anionic detergents.

The nonionic detergents useful herein are preferably ethylene oxideadducts of alkyl phenols which can be represented by the general formulaR -Q-O-wmCm-mm-H wherein R is an alkyl hydrocarbon radical having 8 to20 carbon atoms and'm has a value in the range of 6 to 20. Of thesecompounds the most preferred are those wherein R is a nonyl radical (CI-I or an octyl radical a m)- These adducts are well known and readilyavailable commercially. For example, ethylene oxide adducts of nonylphenols having varying numbers of ethylene oxide units are availablecommercially under the Triton N series from the Rohm & Haas Company,Philadelphia, Pa., and also under the name lgepal" available fromGeneral Aniline Film Corporation, Dyestuff and Chemical Division, andfrom Antara Chemicals. Also, ethylene oxide adducts of octyl phenols areavailable commercially under the Triton X series of Rohm & Haas. Also,these compounds are readily made by one skilled in the art withtechniques well known in the art and therefore, for the sake of brevityand clarity, these known techniques will not be discussed in detail.

Some specific examples of these adducts include the Igepal detergents,shown in the table below, which are composed of ethylene oxide adductsof nonyl phenols, the differences between these detergents using theaverage m value for the ethylene oxide unit.

Detergent Average In lgepal CO 530 6 lgepal CO 610 9 lgepal CO 630 9.5

lgepal CO 710 10.5 lgepal CO 730 lgepal CO 850 In one preferredembodiment R, in the above formula is a nonyl radical, and m has anaverage value of 9.5, e.g., lgepal 630.

The anionic detergents useful herein are preferably those aklylsulfonates represented by the general formula wherein R is an alkylhydrocarbon radical having 8-20 carbon atoms and M is selected fromsodium, potassium, and ammonium.

Examples of some anionic detergents within the scope of the aboveformula are ammonium dodecylbenzene sulfonate, sodium octylbenzenesulfonate, potassium octadecylbenzene sulfonate, and sodiumeicosylbenzene sulfonate.

In one preferred embodiment R" has 12 carbo atoms and M is ammonium,i.e., ammonium dodecylbenzene sulfonate.

It has been noted that the lubricant of this invention is useful tolubricate the passage of a hot thermoplastic material through a closefitting sleeve. Examples of thermoplastic materials useful with thelubricant of this invention include polyethylene, polypropylene,poly(4-methylpentene-l), polybutane, polyhexene, polystyrene, copolymersof ethylene and propylene, ethylene and butene-l, ethylene and hexene-l,styrene and butadiene, polyacrylates such as polymethylmethacrylatepoly(vinylchloride), polyamides, and the like.

The thermoplastic material may contain the additives, fillers,retardants, and the various other agents ordinarily incorporated in suchmaterials prior to extrusion.

The following specific examples are provided to further illustrate thisinvention but not to limit the scope thereof.

EXAMPLE I A mixture of 1 quart distilled water, 1 quart glycerol and 100milliliters of a solution of ammonium dodecyl sulfonate in alcohol(70:30 parts by weight, respectively) (Orvus K Liquid, Procter & Gamble)was prepared and placed in the lubricating tank of an extruded/vacuumsizing equipment train.

One inch OD pipe was extruded using an ethylenehexene-l copolymer,density (D 1505-68) 0.950 and melt index (D1238-65T) 0.20 using aconventional screw type extruder operating at 100 rmp, a barreltemperature of 360400 F., 2,200 psi at die head to produce 15 feetpipe/minute.

The extruded pipe was fed into a cooling water bath at 70 F. through abrass vacuum sizing ring, the face of which was lubricated by a freeflow of the lubricating mixture prepared above at about 1 ml/second.Good surface wetting of the pipe was observed.

The produced pipe had a smooth exterior surface, free of pits andirregularities. There was no polymer hangup at the face plate of thesizing ring after 2 hours of continuous operation.

EXAMPLE II A mixture of one quart distilled water, one quart glyceroland 50 ml of an ethylene oxide adduct of nonyl phenol (lgepal 630, m9.5; Rohm & Haas, Philadelphia, Pa), was prepared and used in anextrusion test as in Example 1.

The product was entirely satisfactory as in Example I and no buildup ofpolymer was observed.

Tests were also made with water and a 50/50 waterglycerol mixture. Thepipe surface, after 15 minutes or less of operation with water, becamestreaked and pitted while polymer buildup became noticeable at the faceplate of the sizing ring. The glycerol-water mixture was better butstreaks developed in the product because the extrudated pipe surface wasnot sufficiently wetted by the detergentless mixture of glycerol andwater. Polymer buildup was again noted.

The water-detergent mixture could not be used because of excessivefoaming.

Reasonable variations and modifications are possible within the scope ofthis disclosure without departing from the spirit and scope thereof.

Having described my invention, that which is claimed '1. An externallubricant useful in the extrusion of thermoplastic goods which consistsessentially of water, a water-soluble polyol of the formula R(OH),wherein R is a multivalent hydrocarbyl radical having 2 to 5 carbonatoms and a valence equal to n, and n is the integer 2 or 3, and atleast one detergent selected from the group consisting of (a) a nonionicdetergent of the forwherein R is an alkyl hydrocarbon radical having 8to 20 carbon atoms and m has a value in the range of 6 to 20 and (b) ananionic detergent of the formula 1 wherein R" is an alkyl hydrocarbonradical having 8 to 20 carbon atoms and M is selected from the groupconsisting of sodium, potassium and ammonium, and wherein the ratio ofsaid polyol to said water is in the range of 0.25 to 1.5 parts by volumepolyol per one part by volume water and further wherein the ratio ofsaid detergent to the combination of said polyol and said water is inthe range of 0.5 to 6 parts by volume detergent per parts by volume ofsaid polyol-water combination.

2. The lubricant of claim'l wherein said polyol is selected from thegroup consisting of glycerol, ethylene glycol and 1,2-propane diol.

3. A lubricant composition according to claim 1 wherein said polyol isglycerol and said detergent is a nonionic detergent wherein R' has 9carbon atoms and m has a value of 9.5

4. A lubricant composition according to claim 1 wherein said polyol isglycerol and said detergent is an anionic detergent wherein R" has 12carbon atoms and M is ammonium.

III

2. The lubricant of claim 1 wherein said polyol is selected from thegroup consisting of glycerol, ethylene glycol and 1,2-propane diol.
 3. Alubricant composition according to claim 1 wherein said polyol isglycerol and said detergent is a nonionic detergent wherein R'' has 9carbon atoms and m has a value of 9.5
 4. A lubricant compositionaccording to claim 1 wherein said polyol is glycerol and said detergentis an anionic detergent wherein R'''' has 12 carbon atoms and M isammonium.